Zoom lens and imaging apparatus

ABSTRACT

A zoom lens is constituted by, in order from the object side: a positive first lens group; a negative second lens group; a positive third lens group; a positive fourth lens group; a negative fifth lens group, and a positive sixth lens group. The distances among adjacent lens groups change when changing magnification from the wide angle end to the telephoto end. The first lens group is constituted by, in order from the object side, a negative lens, a positive lens, and a positive lens. The second lens group has a negative 2R lens group constituted by a cemented lens formed by cementing a negative lens and a positive lens, provided in this order from the object side, together, and a negative single lens. The fifth lens group is constituted by, in order from the object side, a negative lens, a negative lens, and a positive lens.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. §119 to JapanesePatent Application No. 2015-189934 filed on Sep. 28, 2015. The aboveapplication is hereby expressly incorporated by reference, in itsentirety, into the present application.

BACKGROUND

The present disclosure is related to a zoom lens which is particularlyfavorably suited for use in digital cameras, interchangeable lensdigital cameras, and cinematic cameras. The present disclosure is alsorelated to an imaging apparatus equipped with the zoom lens.

Zoom lenses use in digital cameras, interchangeable lens digitalcameras, and cinematic cameras are known, as disclosed in JapaneseUnexamined Patent Publication Nos. 2013-097322 and 2014-209144, as wellas Japanese Patent No. 4585776.

SUMMARY

Recently, the number of pixels in digital cameras, interchangeable lensdigital cameras, and cinematic cameras is increasing. Therefore, thereis demand for a high performance lens, which is compatible with theincreased number of pixels, and that favorably corrects variousaberrations, as a zoom lens to be employed in these cameras. However, itcannot be said that the zoom lenses of Japanese Unexamined PatentPublication Nos. 2013-097322 and 2014-209144, and Japanese Patent No.4585776 have sufficient performance with respect to correcting variousaberrations.

The present disclosure has been developed in view of the foregoingcircumstances. The present disclosure provides a zoom lens whichfavorably corrects various aberrations. The present disclosure alsoprovides an imaging apparatus equipped with such a zoom lens.

A first zoom lens of the present disclosure consists of, in order fromthe object side to the image side:

a first lens group having a positive refractive power;

a second lens group having a negative refractive power;

a third lens group having a positive refractive power;

a fourth lens group having a positive refractive power;

a fifth lens group having a negative refractive power; and

a sixth lens group having a positive refractive power;

the first lens group moving toward the object side, the distance betweenthe first lens group and the second lens group increasing, the distancebetween the second lens group and the third lens group decreasing, thedistance between the third lens group and the fourth lens groupchanging, the distance between the fourth lens group and the fifth lensgroup changing, and the distance between the fifth lens group and thesixth lens group changing, when changing magnification from the wideangle end to the telephoto end;

the first lens group consisting of, in order from the object side to theimage side, a negative 1A lens, a positive 1B lens, and a positive 1Clens;

the second lens group having a 2R lens group having a negativerefractive power as a whole and consisting of a cemented lens formed bycementing a negative lens and a positive lens, which are provided inthis order from the object side to the image side, together, and anegative single lens; and

the fifth lens group consisting of, in order from the object side to theimage side, a negative 5A lens, a negative 5B lens, and a positive 5Clens.

In the zoom lens of the present disclosure, it is preferable forConditional Formula (1) below to be satisfied. Note that it is morepreferable for Conditional Formula (1-1) below to be satisfied.−0.3<f2/f1<−0.1  (1)−0.25<f2/f1<−0.15  (1-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f1 is the paraxial focal length with respectto the d line of the first lens group.

In addition, it is preferable for Conditional Formula (2) below to besatisfied. Note that it is more preferable for Conditional Formula (2-1)below to be satisfied.−0.9<f2/f3<−0.6  (2)−0.8<f2/f3<−0.7  (2-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f3 is the paraxial focal length with respectto the d line of the third lens group.

In addition, it is preferable for the second lens group to have a 2Flens group that includes a cemented lens formed by cementing a positivelens and a negative lens, provided in this order from the object side tothe image side, together, adjacent to the 2R lens group at the objectside thereof.

In addition, it is preferable for Conditional Formula (3) below to besatisfied. Note that it is more preferable for Conditional Formula (3-1)below to be satisfied.0.8<f2/f2R<1.4  (3)1<f2/f2R<1.25  (3-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f2R is the paraxial focal length with respectto the d line of the 2R lens group.

In addition, it is preferable for the 2R lens group to be moved in adirection perpendicular to the optical axis in order to correct forcamera shake.

In addition, it is preferable for the fifth lens group to move towardthe image side when changing focus from that on an object at infinity tothat on an object at a most proximal distance.

In addition, it is preferable for Conditional Formula (4) below to besatisfied. Note that it is more preferable for Conditional Formula (4-1)below to be satisfied.−0.25<f5/f1<−0.05  (4)−0.2<f5/f1<−0.1  (4-1)

wherein f5 is the paraxial focal length with respect to the d line ofthe fifth lens group, and f1 is the paraxial focal length with respectto the d line of the first lens group.

In addition, it is preferable for Conditional Formula (5) below to besatisfied. Note that it is more preferable for Conditional Formula (5-1)below to be satisfied.0.8<f5A/f5<1.3  (5)0.9<f5A/f5<1.2  (5-1)

wherein f5A is the paraxial focal length with respect to the d line ofthe negative 5A lens, and f5 is the paraxial focal length with respectto the d line of the fifth lens group.

In addition, it is preferable for Conditional Formula (6) below to besatisfied. Note that it is more preferable for Conditional Formula (6-1)below to be satisfied.45<(vd5A+vd5B)/2<80  (6)50<(vd5A+vd5B)/2<75  (6-1)

wherein vd5A is the Abbe's number with respect to the d line of thenegative 5A lens, and vd5B is the Abbe's number with respect to the dline of the negative 5B lens.

In addition, it is preferable for the third lens group to have a 3Acemented lens, in which a positive lens and a negative lens provided inthis order from the object side to the image side are cemented together,and a 3B cemented lens, in which a positive lens and a negative lensprovided in this order from the object side to the image side arecemented together.

In addition, it is preferable for a stop to be positioned adjacent tothe third lens group toward the image side thereof, and for the stop tomove integrally with the third lens group when changing magnification.

In addition, it is preferable for the sixth lens group to consist of apositive 6A lens.

An imaging apparatus of the present disclosure is equipped with a zoomlens of the present disclosure described above.

Note that the expression “consists of” means that the zoom lens of thepresent disclosure may also include lenses that practically have nopower, optical elements other than lenses such as a stop, a mask, acover glass, and filters, and mechanical components such as lensflanges, a lens barrel, an imaging element, a camera shake correctingmechanism, etc., in addition to the constituent elements listed above.

In addition, the surface shapes of lenses as well as the signs of therefractive powers of lenses are those which are considered in theparaxial region for lenses that include aspherical surfaces.

The zoom lens of the present disclosure consists of, in order from theobject side to the image side: the first lens group having a positiverefractive power; the second lens group having a negative refractivepower; the third lens group having a positive refractive power; thefourth lens group having a positive refractive power; the fifth lensgroup having a negative refractive power; and the sixth lens grouphaving a positive refractive power. The first lens group moves towardthe object side, the distance between the first lens group and thesecond lens group increases, the distance between the second lens groupand the third lens group decreases, the distance between the third lensgroup and the fourth lens group changes, the distance between the fourthlens group and the fifth lens group changes, and the distance betweenthe fifth lens group and the sixth lens group changes, when changingmagnification from the wide angle end to the telephoto end. The firstlens group consists of, in order from the object side to the image side,a negative 1A lens, a positive 1B lens, and a positive 1C lens. Thesecond lens group has a 2R lens group having a negative refractive poweras a whole and consisting of a cemented lens formed by cementing anegative lens and a positive lens, which are provided in this order fromthe object side to the image side, together, and a negative single lens.The fifth lens group consists of, in order from the object side to theimage side, a negative 5A lens, a negative 5B lens, and a positive 5Clens. Therefore, it is possible for the zoom lens to be that whichfavorably corrects various aberrations.

The imaging apparatus of the present disclosure is equipped with thezoom lens of the present disclosure. Therefore, the imaging apparatuscan obtain images having high image quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a collection of sectional diagrams that illustrate a firstexample of the configuration of a zoom lens according to an embodimentof the present disclosure (which is common with Example 1).

FIG. 2 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 2.

FIG. 3 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 3.

FIG. 4 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 4.

FIG. 5 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 5.

FIG. 6 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 6.

FIG. 7 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 7.

FIG. 8 is a collection of sectional diagrams that illustrate theconfiguration of a zoom lens according to Example 8.

FIG. 9 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 1.

FIG. 10 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 2.

FIG. 11 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 3.

FIG. 12 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 4.

FIG. 13 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 5.

FIG. 14 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 6.

FIG. 15 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 7.

FIG. 16 is a collection of diagrams that illustrate aberrations of thezoom lens of Example 8.

FIG. 17 is a perspective view that illustrates the front side of animaging apparatus as an embodiment of the present disclosure.

FIG. 18 is a perspective view that illustrates the rear side of theimaging apparatus illustrated in FIG. 17.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described indetail with reference to the attached drawings. FIG. 1 is a collectionof sectional diagrams that illustrate the configuration of a zoom lensaccording to an embodiment of the present disclosure. The example of theconfiguration illustrated in FIG. 1 is the same as the configuration ofa zoom lens of Example 1 to be described later. In FIG. 1, the left sideis the object side and the right side is the image side. The aperturestop St illustrated in FIG. 1 does not necessarily represent the size orshape thereof, but the position of the aperture stop St along an opticalaxis Z. In addition, FIG. 1 illustrates an axial light beam wa and alight beam wb at a maximum angle of view.

As illustrated in FIG. 1, the zoom lens of the first embodiment isconstituted by, in order from the object side to the image side: a firstlens group G1 having a positive refractive power, a second lens group G2having a negative refractive power, a third lens group G3 having apositive refractive power, a fourth lens group G4 having a positiverefractive power, a fifth lens group G5 having a negative refractivepower, and a sixth lens group G6 having a positive refractive power.

When this zoom lens is applied to an imaging apparatus, it is preferablefor a cover glass, a prism, and various filters, such as an infraredcutoff filter and a low pass filter, to be provided between the opticalsystem and an imaging surface Sim, depending on the configuration of thecamera to which the lens is mounted. Therefore, FIG. 1 illustrates anexample in which a plane parallel plate shaped optical member PP thatpresumes the presence of such components is provided between the lenssystem and the imaging surface Sim.

This zoom lens is configured such that the first lens group G1constantly moves toward the object side, the distance between the firstlens group G1 and the second lens group G2 constantly increases, thedistance between the second lens group G2 and the third lens group G3constantly decreases, the distance between the third lens group G3 andthe fourth lens group G4 constantly changes, the distance between thefourth lens group G4 and the fifth lens G5 group constantly changes, andthe distance between the fifth lens group G5 and the sixth lens group G6constantly changes, when changing magnification from the wide angle endto the telephoto end. Note that all of the lens groups from among thefirst lens group G1 through the sixth lens group G6 may move, or only aportion of the lens groups may move, when changing magnification.

Adopting such a configuration is advantageous from the viewpoint ofshortening the total length of the lens system. The advantageous effectsof securing telecentric properties and shortening the total length ofthe lens system become particularly prominent in the case that the zoomlens is applied to a non reflex (so called mirrorless) type camera, inwhich back focus is short.

The first lens group G1 is constituted by, in order from the object sideto the image side, a negative 1A lens L1A, a positive 1B lens L1B, and apositive 1C lens L1C. Adopting such a configuration is advantageous fromthe viewpoint of shortening the total length of the lens system. Inaddition, the negative 1A lens L1A bears the function of correctinglongitudinal chromatic aberration, lateral chromatic aberration, andspherical aberration. In addition, providing the two positive lenses,which are the positive 1B lens L1B and the positive 1C lens L1C, enablesthe generation of spherical aberration to be suppressed while securingthe positive refractive power of the first lens group G1 and shorteningthe total length of the lens system.

The second lens group G2 has a 2R lens group G2R having a negativerefractive power as a whole and consisting of a cemented lens formed bycementing a negative lens and a positive lens, which are provided inthis order from the object side to the image side, together, and anegative single lens. The second lens group G2 principally bears thefunction of changing magnification. Here, the cemented lens bears thefunction of suppressing fluctuations in longitudinal chromaticaberration and lateral chromatic aberration when changing magnification.In addition, the negative single lens distributes negative refractivepower with the negative lens within the cemented lens, and bears thefunction of suppressing the generation of spherical aberration,astigmatism, and distortion.

The third lens group G3 bears the principal positive refractive effectof the entire lens system.

The fourth lens group G4 distributes positive refractive power with thethird lens group G3, and bears the function of suppressing thegeneration of spherical aberration and fluctuations in sphericalaberration while changing magnification.

The fifth lens group G5 is constituted by, in order from the object sideto the image side, a negative 5A lens L5A, a negative 5B lens L5B, and apositive 5C lens L5C. By adopting this configuration, fluctuations inastigmatism while changing magnification can be corrected. Here, bypositioning the two negative lenses, which are the negative 5A lens L5Aand the negative 5B lens L5B, toward the object side, the generation ofvarious aberrations can be decreased, while suppressing fluctuations inastigmatism while changing magnification. In addition, the positive 5Clens bears the function of correcting fluctuations in lateral chromaticaberration while changing magnification, by being combined with thenegative 5A lens L5A and the negative 5B lens L5B.

The sixth lens group G6 bears the function of decreasing the incidentangles of light rays at peripheral angles of view that enter an imageformation plane Sim.

It is preferable for Conditional Formula (1) below to be satisfied inthe zoom lens of the present embodiment. Configuring the zoom lens suchthat the value of f2/f1 is not less than or equal to the lower limitdefined in Conditional Formula (1) is advantageous from the viewpoint ofshortening the total length of the lens system at the telephoto end. Inaddition, configuring the zoom lens such that the value of f2/f1 is notgreater than or equal to the upper limit defined in Conditional Formula(1) is advantageous from the viewpoints of correcting longitudinalchromatic aberration and miniaturizing the first lens group G1. Notethat more favorable properties can be obtained in the case thatConditional Formula (1-1) below is satisfied.−0.3<f2/f1<−0.1  (1)−0.25<f2/f1<−0.15  (1-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f1 is the paraxial focal length with respectto the d line of the first lens group.

In addition, it is preferable for Conditional Formula (2) below to besatisfied. Configuring the zoom lens such that the value of f2/f3 is notless than or equal to the lower limit defined in Conditional Formula (2)is advantageous from the viewpoints of suppressing spherical aberrationand suppressing fluctuations in longitudinal chromatic aberration. Inaddition, configuring the zoom lens such that the value of f2/f3 is notgreater than or equal to the upper limit defined in Conditional Formula(2) is advantageous from the viewpoint of maintaining the diameters ofthe lenses of the second lens group G2, the third lens group G3, and thelens groups positioned toward the image side of the third lens group G3small. Note that more favorable properties can be obtained in the casethat Conditional Formula (2-1) below is satisfied.−0.9<f2/f3<−0.6  (2)−0.8<f2/f3<−0.7  (2-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f3 is the paraxial focal length with respectto the d line of the third lens group.

In addition, it is preferable for the second lens group G2 to have a 2Flens group G2F that includes a cemented lens formed by cementing apositive lens and a negative lens, provided in this order from theobject side to the image side, together, adjacent to the 2R lens group2GR at the object side thereof. Adopting such a configuration isadvantageous from the viewpoints of correcting fluctuations inlongitudinal chromatic aberration while changing magnification,suppressing longitudinal chromatic aberration at the telephoto end,aiding the correction of longitudinal chromatic aberration by the firstlens group G1, and shortening the total length of the lens system.

In addition, it is preferable for Conditional Formula (3) below to besatisfied. Configuring the zoom lens such that the value of f2/f2R isnot less than or equal to the lower limit defined in Conditional Formula(3) is advantageous from the viewpoint of securing the magnificationchanging effect of the second lens group G2. In addition, configuringthe zoom lens such that the value of f2/f2R is not greater than or equalto the upper limit defined in Conditional Formula (3) is advantageousfrom the viewpoint of suppressing spherical aberration, astigmatism, anddistortion. Note that more favorable properties can be obtained in thecase that Conditional Formula (3-1) below is satisfied.0.8<f2/f2R<1.4  (3)1<f2/f2R<1.25  (3-1)

wherein f2 is the paraxial focal length with respect to the d line ofthe second lens group, and f2R is the paraxial focal length with respectto the d line of the 2R lens group.

In addition, it is preferable for the 2R lens group G2R to be moved in adirection perpendicular to the optical axis in order to correct forcamera shake. Correcting for camera shake at this position is optimalfor securing sensitivity of the camera shake correcting lenses, and candecrease the amount of movement necessary to correct for camera shake.Therefore, fluctuations in aberrations while correcting for camera shakewill be small, and enlargement of the lens in the radial direction canbe suppressed.

In addition, it is preferable for the fifth lens group G5 to move towardthe image side when changing focus from that on an object at infinity tothat on an object at a most proximal distance. By performing focusingoperations at this position, fluctuations in aberrations during focusingoperations can be kept small. In addition, because the fifth lens groupG5 is positioned at the image side of the third lens group G3 and thefourth lens group G4, which have positive refractive powers, the sizethereof in the radial direction can be decreased, which facilitatesweight reduction of the fifth lens group G5. Such a configuration isadvantageous from the viewpoint of performing high speed focusingoperations.

In addition, it is preferable for Conditional Formula (4) below to besatisfied. Configuring the zoom lens such that the value of f5/f1 is notless than or equal to the lower limit defined in Conditional Formula (4)enables the amount of movement of the fifth lens group G5 to bedecreased, which is advantageous from the viewpoint of shortening thetotal length of the lens system. In addition, configuring the zoom lenssuch that the value of f5/f1 is not greater than or equal to the upperlimit defined in Conditional Formula (4) is advantageous from theviewpoint of suppressing fluctuations in astigmatism. Note that morefavorable properties can be obtained in the case that ConditionalFormula (4-1) below is satisfied.−0.25<f5/f1<−0.05  (4)−0.2<f5/f1<−0.1  (4-1)

wherein f5 is the paraxial focal length with respect to the d line ofthe fifth lens group, and f1 is the paraxial focal length with respectto the d line of the first lens group.

In addition, it is preferable for Conditional Formula (5) below to besatisfied. Configuring the zoom lens such that the value of f5A/f5 isnot less than or equal to the lower limit defined in Conditional Formula(5) is advantageous from the viewpoint of suppressing the generation ofspherical aberration. In addition, configuring the zoom lens such thatthe value of f5A/f5 is not greater than or equal to the upper limitdefined in Conditional Formula (5) is advantageous from the viewpointsof suppressing astigmatism. Note that more favorable properties can beobtained in the case that Conditional Formula (5-1) below is satisfied.0.8<f5A/f5<1.3  (5)0.9<f5A/f5<1.2  (5-1)

wherein f5A is the paraxial focal length with respect to the d line ofthe negative 5A lens, and f5 is the paraxial focal length with respectto the d line of the fifth lens group.

In addition, it is preferable for Conditional Formula (6) below to besatisfied. Configuring the zoom lens such that the value of(vd5A+vd5B)/2 is not less than or equal to the lower limit defined inConditional Formula (6) is advantageous from the viewpoints ofcorrecting lateral chromatic aberration and suppressing fluctuations inlateral chromatic aberration while changing magnification. In addition,there is a tendency for the refractive index to decrease as the Abbe'snumber increases. Therefore, it is necessary to secure refractive powerby decreasing the curvatures of lenses. For this reason, configuring thezoom lens such that the value of (vd5A+vd5B)/2 is not greater than orequal to the upper limit defined in Conditional Formula (6) isadvantageous from the viewpoint of preventing the lenses from becomingexcessively large. Note that more favorable properties can be obtainedin the case that Conditional Formula (6-1) below is satisfied.45<(vd5A+vd5B)/2<80  (6)50<(vd5A+vd5B)/2<75  (6-1)

wherein vd5A is the Abbe's number with respect to the d line of thenegative 5A lens, and vd5B is the Abbe's number with respect to the dline of the negative 5B lens.

In addition, it is preferable for the third lens group to have, in orderfrom the object side to the image side, a positive single lens, a 3Acemented lens (the cemented constituted by a lens L3B and a lens L3C inFIG. 1), in which a positive lens and a negative lens provided in thisorder from the object side to the image side are cemented together, anda 3B cemented lens (the cemented constituted by a lens L3D and a lensL3E in FIG. 1), in which a positive lens and a negative lens provided inthis order from the object side to the image side are cemented together.Adopting such a configuration is advantageous from the viewpoints ofreducing the diameters of the lenses and correcting vertical chromaticaberration. Here, the positive single lens exhibits the effect ofdecreasing the diameters of the lenses included in the third lens groupG3 and the lens groups positioned at the image side of the third lensgroup G3. In addition, the two cemented lenses exhibit the advantageouseffects of correcting longitudinal chromatic aberration and colorbleeding caused by color shifts of spherical aberration.

In addition, it is preferable for an aperture stop St to be positionedadjacent to the third lens group G3 toward the image side thereof, andfor the aperture stop St to move integrally with the third lens group G3when changing magnification. Positioning the aperture stop St at theimage side of the third lens group G3 in this manner is advantageousfrom the viewpoint of miniaturizing a stop unit.

In addition, it is preferable for the sixth lens group G6 to consist ofa positive 6A lens L6A. If the number of lenses within the sixth lensgroup G6 increases and the thickness thereof increases, it will becomenecessary to increase the negative refractive power of the second lensgroup G2 or the fifth lens group G5. This will result in an increase influctuations of spherical aberration. Therefore, constituting the sixthlens group G6 by a single lens in this manner is advantageous from theviewpoint of suppressing fluctuations in spherical aberration.

In the case that the present zoom lens is to be utilized in anenvironment in which the zoom lens is likely to be damaged, it ispreferable for a protective multiple layer film coating to beadministered. Further, a reflection preventing coating may beadministered in order to reduce the amount of ghost light during use, inaddition to the protective coating.

In addition, FIG. 1 illustrates an example in which the optical memberPP is provided between the lens system and the imaging surface Sim.Alternatively, various filters such as low pass filters and filters thatcut off specific wavelength bands may be provided among each of thelenses instead of being provided between the lens system and the imagingsurface Sim. As a further alternative, coatings that have the samefunctions as the various filters may be administered on the surfaces ofthe lenses.

Next, examples of numerical values of the zoom lens of the presentdisclosure will be described.

First, the zoom lens of Example 1 will be described. FIG. 1 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 1. Note that in FIG. 1 and FIGS. 2 through 8that correspond to Examples 2 through 8 to be described later, the leftside is the object side, the right side is the image side, and theaperture stops St in the drawings do not necessarily represent the sizeor the shape thereof, but the position thereof along the optical axis Z.

In the zoom lens of Example 1, the first lens group G1 is constituted bythree lenses, which are lenses L1A through L1C, the second lens group G2is constituted by five lenses, which are lenses L2A through L2E, thethird lens group G3 is constituted by five lenses, which are lenses L3Athrough L3E, the fourth lens group G4 is constituted by four lenses,which are lenses L4A through L4D, the fifth lens group G5 is constitutedby three lenses, which are lenses L5A through L5C, and the sixth lensgroup G6 is constituted by one lens, which is a lens L6A. The secondlens group G2 is constituted by, in order from the object side to theimage side, a 2F lens group G2F and a 2R lens group G2R. The 2F lensgroup G2F is constituted by a cemented lens, formed by cementing apositive lens L2A and a negative lens L2B, provided in this order fromthe object side to the image side, together. The 2R lens group G2R isconstituted by, in order from the object side to the image side, acemented lens, formed by cementing a negative lens L2C and a positivelens L2D together, and a negative single lens L2E.

Basic lens data are shown in Table 1, data related to various items areshown in Table 2, and data related to the distances among movablesurfaces are shown in Table 3, for the zoom lens of Example 1. In thefollowing description, the meanings of the symbols in the tables will bedescribed for Example 1. The meanings of the symbols are basically thesame for Examples 2 and 8.

In the lens data of Table 1, surface numbers that sequentially increasefrom the object side to the image side, with the surface of theconstituent element at the most object side designated as first, areshown in the column “Surface Number”. The radii of curvature of ithsurfaces are shown in the column of “Radius of Curvature”, the distancesalong the optical axis Z between each surface and a next surface areshown in the column “Distance”. The refractive indices of each opticalelement with respect to the d line (wavelength: 587.6 nm) are shown inthe column nd. The Abbe's numbers of each optical element with respectto the d line (wavelength: 587.6 nm) are shown in the column vd. Thepartial dispersion ratio of each optical element is shown in the column“θgF”.

Note that the partial dispersion ratio θgF is represented by the formulabelow.θgF=(ng−nF)/(nF−nC)

wherein ng is the refractive index with respect to the g line, nF is therefractive index with respect to the F line, and nC is the refractiveindex with respect to the C line.

Here, the signs of the radii of curvature are positive in cases that thesurface shape is convex toward the object side, and negative in casesthat the surface shape is convex toward the image side. The aperturestop St and the optical member PP are also included in the basic lensdata. Text reading “(aperture stop)” is indicated along with a surfacenumber in the column of the surface numbers at the surface correspondingto the aperture stop. In addition, DD [surface number] is indicated inthe column “Distance” for distances that change while changingmagnification. The numerical values corresponding to DD [surface number]are shown in Table 3.

Table 2 shows the values of the zoom magnification rates of the entiresystem, the focal lengths “f”, the F numbers “F No.”, and the fullangles of view “2ω” at the wide angle end, at an intermediate position,and at the telephoto end, respectively, as the data related to variousitems.

In the basic lens data, the data related to various items, and the datarelated to the distances among movable surfaces, mm are used as theunits for lengths and degrees are used as the units for angles. However,it is possible for optical systems to be proportionately enlarged orproportionately reduced and utilized. Therefore, other appropriate unitsmay be used.

TABLE 1 Example 1: Lens Data Surface Radius of Number Curvature Distancend νd θgF 1 269.48203 2.220 1.83481 42.72 0.56486 2 107.65000 8.4501.49700 81.54 0.53748 3 −666.67333 0.150 4 96.62397 7.950 1.43875 94.660.53402 5 ∞ DD [5]  6 −208.69230 3.690 1.60562 43.71 0.57214 7 −38.623001.000 1.75500 52.32 0.54765 8 −78.91650 2.300 9 −167.21335 1.010 1.5952267.73 0.54426 10 25.00500 3.090 1.78470 26.29 0.61360 11 44.82826 2.87012 −69.05525 1.000 1.81600 46.62 0.55682 13 193.37055 DD [13] 1471.43178 5.720 1.58913 61.13 0.54067 15 −44.45211 0.150 16 39.586956.530 1.49700 81.54 0.53748 17 −33.11400 1.000 1.90043 37.37 0.57720 18139.34617 0.180 19 28.83700 6.700 1.58267 46.42 0.56716 20 −28.837001.000 1.51742 52.43 0.55649 21 21.27628 2.780 22 (stop) ∞ DD [22] 2349.78064 4.670 1.49700 81.54 0.53748 24 −56.44194 0.330 25 −40.486971.000 1.83481 42.72 0.56486 26 −448.89591 0.170 27 40.52272 1.0101.69700 48.52 0.55889 28 20.75000 4.300 1.51742 52.43 0.55649 29−43.73001 DD [29] 30 92.44720 1.000 1.61800 63.33 0.54414 31 16.394212.630 32 ∞ 1.010 1.49700 81.54 0.53748 33 14.90900 4.450 1.69350 53.200.54731 34 53.22030 DD [34] 35 −249.66626 2.910 1.54072 47.23 0.56511 36−49.77001 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞ 0.700 1.4978454.95 0.54959 39 ∞ 1.000

TABLE 2 Example 1: Items (d line) Wide Angle Intermediate Telephoto ZoomRatio 1.0 1.7 3.8 f′ 102.873 178.159 387.872 FNo. 4.62 4.79 5.78 2ω (°)15.6 9.0 4.2

TABLE 3 Example 1: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 47.912 84.375 109.566 DD [13] 28.89319.144 1.765 DD [22] 11.359 7.991 24.280 DD [29] 7.202 7.574 2.343 DD[34] 5.165 17.208 27.898 DD [36] 36.048 28.853 29.788

FIG. 9 is a collection of diagrams that illustrate various aberrationsof the zoom lens of Example 1. The spherical aberration, theastigmatism, the distortion, and the lateral chromatic aberration of thezoom lens of Example 1 at the wide angle end are illustrated in thisorder from the left side of the drawing sheet at the upper portion ofFIG. 5. The spherical aberration, the astigmatism, the distortion, andthe lateral chromatic aberration of the zoom lens of Example 1 at anintermediate focal distance are illustrated are illustrated in thisorder from the left side of the drawing sheet at the middle portion ofFIG. 5. The spherical aberration, the astigmatism, the distortion, andthe lateral chromatic aberration of the zoom lens of Example 1 at thetelephoto end are illustrated in are illustrated in this order from theleft side of the drawing sheet at the lower portion of FIG. 5. Each ofthe aberration diagrams show aberrations using the d line (wavelength:587.6 nm) as a reference wavelength. The diagrams that illustratespherical aberration show aberrations related to the d line (wavelength:587.6 nm), aberrations related to the C line (wavelength: 656.3 nm),aberrations related to the F line (wavelength: 486.1 nm), andaberrations related to the g line (wavelength: 435.8 nm) as solid lines,long broken lines, short broken lines, and solid gray lines,respectively. In the diagrams that illustrate astigmatism, aberrationsin the sagittal direction and aberrations in the tangential directionare indicated by solid lines and short broken lines, respectively. Inthe diagrams that illustrate lateral chromatic aberration, aberrationsrelated to the C line (wavelength: 656.3 nm), aberrations related to theF line (wavelength: 486.1 nm), and aberrations related to the g line(wavelength: 435.8 nm) are shown as long broken lines, short brokenlines, and solid gray lines, respectively. Note that these verticalaberrations are all for a state focused on an object at infinity. In thediagrams that illustrate spherical aberrations, “F No.” denotes Fvalues. In the other aberration diagrams, “ω” denotes half angles ofview.

The symbols, the meanings, and the manner in which the data are shown inthe description of Example 1 above are the same for the followingExamples to be described later, unless particularly noted. Therefore,redundant descriptions thereof will be omitted below.

Next, a zoom lens according to Example 2 will be described. FIG. 2 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 2. The number of lenses in each lens groupwithin the zoom lens of Example 2 is the same as those for Example 1.Basic lens data are shown in Table 4, data related to various items areshown in Table 5, data related to the distances among movable surfacesare shown in Table 6, and various aberrations are illustrated in FIG. 10for the zoom lens of Example 2.

TABLE 4 Example 2: Lens Data Surface Radius of Number Curvature Distancend νd θgF 1 258.99426 2.220 1.83481 42.72 0.56486 2 105.99457 8.3701.49700 81.54 0.53748 3 −813.40013 0.150 4 96.96234 8.250 1.43875 94.660.53402 5 −12541.90626 DD [5]  6 −228.16128 3.720 1.60562 43.71 0.572147 −38.90795 1.000 1.75500 52.32 0.54765 8 −80.70102 2.300 9 −168.519611.010 1.59522 67.73 0.54426 10 24.91505 3.114 1.78470 26.29 0.61360 1144.46548 2.958 12 −68.97092 1.000 1.81600 46.62 0.55682 13 198.22555 DD[13] 14 70.13675 5.340 1.58913 61.13 0.54067 15 −44.50451 0.150 1638.68170 6.653 1.49700 81.54 0.53748 17 −33.05588 1.000 1.90043 37.370.57720 18 138.23933 0.668 19 29.56207 6.760 1.58267 46.42 0.56716 20−27.52545 1.000 1.51742 52.43 0.55649 21 21.28674 2.738 22 (stop) ∞ DD[22] 23 51.18087 3.962 1.49700 81.54 0.53748 24 −58.76135 0.287 25−41.01946 1.000 1.83481 42.72 0.56486 26 −442.07391 0.150 27 40.217471.010 1.69700 48.52 0.55889 28 20.72664 4.266 1.51742 52.43 0.55649 29−43.41757 DD [29] 30 117.47452 1.000 1.61800 63.33 0.54414 31 16.997482.597 32 274.37374 1.010 1.49700 81.54 0.53748 33 15.00523 4.204 1.6935053.20 0.54731 34 46.29321 DD [34] 35 −252.89772 3.324 1.54072 47.230.56511 36 −48.70676 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞ 0.7001.49784 54.95 0.54959 39 ∞ 1.000

TABLE 5 Example 2: Items (d line) Wide Angle Intermediate Telephoto ZoomRatio 1.0 1.7 3.8 f′ 102.898 178.202 387.966 FNo. 4.62 4.82 5.78 2ω (°)15.6 9.0 4.2

TABLE 6 Example 2: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 47.985 84.100 110.054 DD [13] 29.20919.050 1.658 DD [22] 11.087 7.995 23.693 DD [29] 7.254 7.894 2.707 DD[34] 5.281 16.955 27.046 DD [36] 35.935 29.107 30.587

Next, a zoom lens according to Example 3 will be described. FIG. 3 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 3. The number of lenses in each lens groupwithin the zoom lens of Example 3 is the same as those for Example 1.Basic lens data are shown in Table 7, data related to various items areshown in Table 8, data related to the distances among movable surfacesare shown in Table 9, and various aberrations are illustrated in FIG. 11for the zoom lens of Example 3.

TABLE 7 Example 3: Lens Data Surface Radius of Number Curvature Distancend νd θgF 1 262.40932 2.220 1.83481 42.72 0.56486 2 105.54031 8.3841.49700 81.54 0.53748 3 −733.03668 0.150 4 95.96727 7.808 1.43387 95.180.53733 5 −15644.45936 DD [5]  6 −228.28533 3.522 1.58267 46.42 0.567167 −38.72547 0.900 1.69680 55.53 0.54341 8 −85.18699 2.301 9 −172.242350.910 1.59522 67.73 0.54426 10 23.88538 3.576 1.78470 26.29 0.61360 1146.63101 2.720 12 −78.62778 0.900 1.83481 42.72 0.56486 13 120.57303 DD[13] 14 62.51644 5.042 1.60311 60.64 0.54148 15 −44.95879 0.150 1637.70765 6.383 1.49700 81.54 0.53748 17 −32.17618 0.800 1.90043 37.370.57720 18 122.86192 1.690 19 28.87948 6.260 1.58267 46.42 0.56716 20−26.63471 0.800 1.51742 52.43 0.55649 21 20.72606 2.745 22 (stop) ∞ DD[22] 23 50.07194 2.519 1.49700 81.54 0.53748 24 −74.92532 0.437 25−40.58758 0.700 1.72000 41.98 0.57299 26 −885.62981 0.174 27 38.599550.710 1.72000 43.69 0.56995 28 20.36324 4.380 1.51742 52.43 0.55649 29−42.13900 DD [29] 30 133.32611 0.700 1.61800 63.33 0.54414 31 17.237142.422 32 207.21027 0.710 1.49700 81.54 0.53748 33 14.95626 3.161 1.6970048.52 0.55889 34 49.34035 DD [34] 35 −251.94791 2.500 1.51742 52.430.55649 36 −51.99972 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞ 0.7001.49784 54.95 0.54959 39 ∞ 1.000

TABLE 8 Example 3: Items (d line) Wide Angle Intermediate Telephoto ZoomRatio 1.0 1.7 3.8 f′ 102.890 178.188 387.935 FNo. 4.62 4.72 5.78 2ω (°)15.6 9.0 4.2

TABLE 9 Example 3: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 48.275 84.574 110.603 DD [13] 28.06116.145 1.643 DD [22] 11.932 7.999 24.129 DD [29] 6.601 8.569 2.281 DD[34] 5.219 15.525 30.943 DD [36] 38.604 30.180 28.730

Next, a zoom lens according to Example 4 will be described. FIG. 4 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 4. The number of lenses in each lens groupwithin the zoom lens of Example 4 is the same as those for Example 1.Basic lens data are shown in Table 10, data related to various items areshown in Table 11, data related to the distances among movable surfacesare shown in Table 12, and various aberrations are illustrated in FIG.12 for the zoom lens of Example 4.

TABLE 10 Example 4: Lens Data Surface Radius of Number CurvatureDistance nd νd θgF 1 261.69144 2.220 1.83481 42.72 0.56486 2 107.038809.000 1.49700 81.54 0.53748 3 −1029.68373 0.150 4 97.17921 8.700 1.4387594.94 0.53433 5 −32440.75797 DD [5]  6 −405.23012 3.939 1.59551 39.240.58043 7 −46.61633 1.000 1.72916 54.68 0.54451 8 −99.92995 2.800 9−613.56320 1.010 1.59522 67.73 0.54426 10 29.81511 3.000 1.84666 23.780.62054 11 46.91136 3.549 12 −71.42841 1.000 1.83481 42.72 0.56486 13173.10115 DD [13] 14 81.36754 5.121 1.64000 60.08 0.53704 15 −58.058550.150 16 35.63695 7.010 1.49700 81.54 0.53748 17 −44.63558 1.000 1.9108235.25 0.58224 18 146.58133 2.000 19 43.19398 7.010 1.63980 34.47 0.5923320 −24.82487 1.000 1.59551 39.24 0.58043 21 25.47397 2.681 22 (stop) ∞DD [22] 23 53.92651 5.000 1.49700 81.54 0.53748 24 −78.38535 0.803 25−33.76811 1.000 1.60562 43.71 0.57214 26 −100.32701 1.500 27 43.039991.010 1.80100 34.97 0.58642 28 22.43546 5.000 1.51742 52.43 0.55649 29−39.11154 DD [29] 30 117.68560 1.000 1.61800 63.33 0.54414 31 17.302642.500 32 −156.38439 1.010 1.49700 81.54 0.53748 33 15.76729 4.2761.66672 48.32 0.56101 34 104.68410 DD [34] 35 660.95421 3.000 1.5174252.43 0.55649 36 −79.06941 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞0.700 1.49784 54.95 0.54959 39 ∞ 1.000

TABLE 11 Example 4: Items (d line) Wide Angle Intermediate TelephotoZoom Ratio 1.0 1.7 3.8 f′ 102.916 178.233 388.034 FNo. 4.12 4.15 5.77 2ω(°) 15.6 9.0 4.2

TABLE 12 Example 4: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 47.161 87.165 104.964 DD [13] 32.18721.866 1.653 DD [22] 10.237 11.976 38.739 DD [29] 7.014 5.989 2.291 DD[34] 4.801 11.403 26.526 DD [36] 34.730 29.228 30.955

Next, a zoom lens according to Example 5 will be described. FIG. 5 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 5. The number of lenses in each lens groupwithin the zoom lens of Example 5 is the same as those for Example 1.Basic lens data are shown in Table 13, data related to various items areshown in Table 14, data related to the distances among movable surfacesare shown in Table 15, and various aberrations are illustrated in FIG.13 for the zoom lens of Example 5.

TABLE 13 Example 5: Lens Data Surface Radius of Number CurvatureDistance nd νd θgF 1 246.81462 2.220 1.83481 42.72 0.56486 2 107.737838.041 1.49700 81.54 0.53748 3 −1178.90109 0.150 4 100.44029 7.5881.43875 94.94 0.53433 5 8727.25727 DD [5]  6 3024.98867 3.778 1.6228057.05 0.54640 7 −45.65466 1.000 1.71299 53.87 0.54587 8 −116.96443 2.3009 −238.80952 1.010 1.72916 54.68 0.54451 10 23.51336 3.723 1.78472 25.680.61621 11 55.94830 2.570 12 −68.95561 1.000 1.81600 46.62 0.55682 13274.76383 DD [13] 14 81.51290 4.680 1.69680 55.53 0.54341 15 −51.957890.150 16 37.45190 6.447 1.49700 81.54 0.53748 17 −35.34266 1.000 1.9004337.37 0.57720 18 95.27503 2.000 19 30.80965 6.418 1.65412 39.68 0.5737820 −29.75104 1.000 1.56732 42.82 0.57309 21 21.59194 2.620 22 (stop) ∞DD [22] 23 43.75714 4.404 1.53775 74.70 0.53936 24 −56.69385 0.264 25−40.80586 1.000 1.83400 37.16 0.57759 26 1196.79400 0.150 27 46.193051.010 1.69680 55.53 0.54341 28 21.65972 4.255 1.51742 52.43 0.55649 29−39.14434 DD [29] 30 168.89036 1.000 1.61800 63.33 0.54414 31 18.062371.718 32 74.24649 1.010 1.49700 81.54 0.53748 33 14.51063 3.101 1.6970048.52 0.55889 34 31.80102 DD [34] 35 −250.02232 3.000 1.58144 40.750.57757 36 −49.91039 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞ 0.7001.49784 54.95 0.54959 39 ∞ 1.000

TABLE 14 Example 5: Items (d line) Wide Angle Intermediate TelephotoZoom Ratio 1.0 1.7 3.8 f′ 102.913 178.227 388.020 FNo. 4.62 4.62 5.78 2ω(°) 15.4 8.8 4.2

TABLE 15 Example 5: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 49.840 89.688 115.040 DD [13] 30.47818.097 1.637 DD [22] 9.119 8.194 22.721 DD [29] 7.515 8.383 2.292 DD[34] 5.566 11.100 28.523 DD [36] 35.737 30.040 29.656

Next, a zoom lens according to Example 6 will be described. FIG. 6 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 6. The number of lenses in each lens groupwithin the zoom lens of Example 6 is the same as those for Example 1.Basic lens data are shown in Table 16, data related to various items areshown in Table 17, data related to the distances among movable surfacesare shown in Table 18, and various aberrations are illustrated in FIG.14 for the zoom lens of Example 6.

TABLE 16 Example 6: Lens Data Surface Radius of Number CurvatureDistance nd νd θgF 1 245.80950 2.220 1.83481 42.72 0.56486 2 107.218768.092 1.49700 81.54 0.53748 3 −1141.17154 0.100 4 100.21881 7.6541.43875 94.94 0.53433 5 33201.75554 DD [5]  6 −1239.59270 3.888 1.6516058.55 0.54267 7 −41.76492 1.000 1.72916 54.68 0.54451 8 −115.23571 2.4259 −199.35565 1.010 1.72916 54.68 0.54451 10 23.60406 3.677 1.80518 25.420.61616 11 54.68729 2.600 12 −69.50409 1.000 1.78800 47.37 0.55598 13258.80679 DD [13] 14 85.79751 4.693 1.69680 55.53 0.54341 15 −51.098390.100 16 38.11402 6.458 1.49700 81.54 0.53748 17 −36.18138 1.000 1.9004337.37 0.57720 18 103.37686 2.000 19 29.99892 6.510 1.65412 39.68 0.5737820 −31.15673 1.000 1.57501 41.50 0.57672 21 21.50234 3.015 22 (stop) ∞DD [22] 23 50.39261 3.623 1.59522 67.73 0.54426 24 −62.84452 0.576 25−39.96783 1.000 1.83400 37.16 0.57759 26 415.94560 0.100 27 41.918541.010 1.67790 55.34 0.54726 28 20.11580 4.530 1.51742 52.43 0.55649 29−37.22510 DD [29] 30 175.42627 1.000 1.61800 63.33 0.54414 31 18.818961.473 32 75.02252 1.010 1.49700 81.54 0.53748 33 13.84323 3.383 1.6177249.81 0.56035 34 34.75715 DD [34] 35 −250.01927 3.000 1.58144 40.750.57757 36 −50.02712 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞ 0.7001.49784 54.95 0.54959 39 ∞ 1.000

TABLE 17 Example 6: Items (d line) Wide Angle Intermediate TelephotoZoom Ratio 1.0 1.7 3.8 f′ 102.923 178.245 388.060 FNo. 4.62 4.62 5.78 2ω(°) 15.4 8.8 4.2

TABLE 18 Example 6: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 49.385 88.916 113.805 DD [13] 29.80817.927 1.644 DD [22] 9.485 8.115 22.489 DD [29] 7.405 8.241 2.295 DD[34] 5.476 11.478 28.535 DD [36] 35.816 30.022 29.729

Next, a zoom lens according to Example 7 will be described. FIG. 7 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 7. The number of lenses in each lens groupwithin the zoom lens of Example 7 is the same as those for Example 1,except that a third lens group G3 is constituted by six lenses, whichare lenses L3A through L3F, and a fourth lens group G4 is constituted bythree lenses, which are lenses L4A through L4C. Basic lens data areshown in Table 19, data related to various items are shown in Table 20,data related to the distances among movable surfaces are shown in Table21, and various aberrations are illustrated in FIG. 15 for the zoom lensof Example 7.

TABLE 19 Example 7: Lens Data Surface Radius of Number CurvatureDistance nd νd θgF 1 205.08632 2.220 1.81600 46.62 0.55682 2 93.670798.130 1.49700 81.54 0.53748 3 2342.19599 0.100 4 98.54896 7.622 1.4970081.54 0.53748 5 3673.27806 DD [5]  6 −289.23356 4.022 1.74000 28.300.60790 7 −36.10761 1.000 1.80000 29.84 0.60178 8 −110.09634 0.800 9645.89060 1.010 1.81600 46.62 0.55682 10 29.78983 2.851 1.84666 23.780.62054 11 54.70693 2.724 12 −68.62504 1.000 1.78800 47.37 0.55598 13182.50252 DD [13] 14 99.12755 4.088 1.49700 81.54 0.53748 15 −62.623950.100 16 54.04337 3.841 1.68893 31.07 0.60041 17 −167.10465 0.100 1831.95590 5.235 1.43875 94.94 0.53433 19 −71.94599 1.000 2.00069 25.460.61364 20 35.97289 0.250 21 21.83290 6.010 1.72342 37.95 0.58370 22−1067.02913 1.000 1.60738 56.82 0.54840 23 18.31437 2.848 24 (stop) ∞ DD[24] 25 35.66698 5.000 1.51742 52.43 0.55649 26 138.42208 1.000 27102.65914 5.008 1.51742 52.43 0.55649 28 −22.15929 1.000 1.74400 44.790.56560 29 −43.98564 DD [29] 30 249.15741 1.000 1.72916 54.68 0.54451 3118.44686 1.340 32 51.46462 1.010 1.65160 58.55 0.54267 33 13.37706 3.3231.83481 42.72 0.56486 34 30.11090 DD [34] 35 −186.41513 3.668 1.6034238.03 0.58356 36 −37.12873 DD [36] 37 ∞ 2.150 1.54763 54.99 0.55229 38 ∞0.700 1.49784 54.95 0.54959 39 ∞ 1.000

TABLE 20 Example 7: Items (d line) Wide Angle Intermediate TelephotoZoom Ratio 1.0 1.5 2.7 f′ 144.132 217.169 388.166 FNo. 4.62 5.01 5.79 2ω(°) 10.8 7.4 4.0

TABLE 21 Example 7: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 69.227 91.984 109.320 DD [13] 17.78415.481 1.451 DD [24] 6.777 6.731 28.472 DD [29] 10.181 6.252 1.493 DD[34] 4.767 20.380 21.512 DD [36] 30.154 28.407 30.673

Next, a zoom lens according to Example 8 will be described. FIG. 8 is acollection of sectional diagrams that illustrate the lens configurationof the zoom lens of Example 8. The number of lenses in each lens groupwithin the zoom lens of Example 8 is the same as those for Example 7.Basic lens data are shown in Table 22, data related to various items areshown in Table 23 data related to the distances among movable surfacesare shown in Table 24, and various aberrations are illustrated in FIG.16 for the zoom lens of Example 8.

TABLE 22 Example 8: Lens Data Surface Radius of Number CurvatureDistance nd νd θgF 1 212.35539 2.220 1.81600 46.62 0.55682 2 95.180818.438 1.49700 81.54 0.53748 3 −5352.69979 0.100 4 97.19575 7.794 1.4970081.54 0.53748 5 3569.72565 DD [5]  6 −1035.11505 3.647 1.73800 32.260.58995 7 −43.87339 1.000 1.80100 34.97 0.58642 8 −192.33037 1.000 9−798.53909 1.010 1.72916 54.68 0.54451 10 25.08611 3.212 1.80518 25.420.61616 11 47.70304 2.731 12 −77.43380 1.000 1.91082 35.25 0.58224 13406.69358 DD [13] 14 95.54044 4.039 1.49700 81.54 0.53748 15 −60.885280.100 16 54.73332 3.551 1.58144 40.75 0.57757 17 −222.60779 0.100 1829.15355 5.233 1.49700 81.54 0.53748 19 −84.20866 1.000 1.91650 31.600.59117 20 31.50556 0.250 21 22.36049 5.250 1.71700 47.93 0.56062 22−70.12504 1.000 1.65160 58.55 0.54267 23 19.36813 2.705 24 (stop) ∞ DD[24] 25 35.91871 2.799 1.51742 52.43 0.55649 26 156.71491 1.000 2786.24955 3.482 1.51742 52.43 0.55649 28 −29.49271 1.000 1.61405 54.990.55092 29 −110.87437 DD [29] 30 228.50744 1.000 1.75500 52.32 0.5476531 21.26842 2.600 32 64.84575 1.010 1.61800 63.33 0.54414 33 16.329793.042 1.80400 46.58 0.55730 34 34.04170 DD [34] 35 423.63050 4.5531.78800 47.37 0.55598 36 −54.10936 DD [36] 37 ∞ 2.150 1.54763 54.990.55229 38 ∞ 0.700 1.49784 54.95 0.54959 39 ∞ 1.000

TABLE 23 Example 8: Items (d line) Wide Angle Intermediate TelephotoZoom Ratio 1.0 1.5 2.7 f′ 144.115 217.143 388.119 FNo. 4.57 5.08 5.79 2ω(°) 11.0 7.4 4.2

TABLE 24 Example 8: Distances Among Movable Surfaces Wide AngleIntermediate Telephoto DD [5] 67.325 86.464 104.178 DD [13] 16.78913.866 1.475 DD [24] 7.697 3.807 27.092 DD [29] 12.949 8.729 1.496 DD[34] 7.996 30.300 36.010 DD [36] 28.165 28.165 28.165

Table 25 shows values corresponding to Conditional Formulae (1) through(6) for the zoom lenses of Examples 1 through 8. Note that all of theExamples use the d line as a reference wavelength, and the values shownin Table 25 are those with respect to the reference wavelength.

TABLE 25 Formula Condition Example 1 Example 2 Example 3 Example 4Example 5 Example 6 Example 7 Example 8 (1) f2/f1 −0.195 −0.194 −0.191−0.211 −0.198 −0.196 −0.200 −0.205 (2) f2/f3 −0.754 −0.763 −0.772 −0.738−0.777 −0.777 −0.778 −0.750 (3) f2/f2R 1.116 1.120 1.111 1.145 1.2041.181 1.125 1.083 (4) f5/f1 −0.168 −0.164 −0.175 −0.172 −0.153 −0.155−0.136 −0.156 (5) f5A/f5 1.013 1.021 0.956 0.966 1.065 1.108 1.057 1.108(6) (νd5A + νd5B)/2 72.4 72.4 72.4 72.4 72.4 72.4 56.6 57.8

Based on the data above, it can be understood that all of the zoomlenses of Examples 1 through 8 satisfy Conditional Formulae (1) through(6), and that these zoom lenses are those in which various aberrationsare favorably corrected.

Next, an imaging apparatus according to an embodiment of the presentdisclosure will be described with reference to FIG. 17 and FIG. 18. FIG.17 and FIG. 18 respectively are perspective views of the front and therear of a camera 30. The camera 30 is a non reflex (so calledmirrorless) digital camera, onto which an exchangeable lens 20 isinterchangeably mounted. The exchangeable lens 20 is a zoom lens 1according to an embodiment of the present disclosure housed in a lensbarrel.

The camera 30 is equipped with a camera body 31. A shutter releasebutton 32 and a power button 33 are provided on the upper surface of thecamera body 31. Operating sections 34 and 35 and a display section 36are provided on the rear surface of the camera body 31. The displaysection 36 displays images which have been photographed and imageswithin the angle of view prior to photography.

A photography opening, in to which light from targets of photographyenters, is provided at the central portion of the front surface of thecamera body 31. A mount 37 is provided at a position corresponding tothe photography opening. The exchangeable lens 20 is mounted onto thecamera body 31 via the mount 37.

An imaging element (not shown), such as a CCD that receives images ofsubjects formed by the exchangeable lens 20 and outputs image signalscorresponding to the images, a signal processing circuit (not shown)that processes the image signals output by the imaging element togenerate images, and a recording medium (not shown) for recording thegenerated images, are provided within the camera body 31. In this camera30, photography of a still image corresponding to a single frame orvideo imaging is enabled by pressing the shutter release button 32.Image data obtained by photography or video imaging are recorded in therecording medium.

The camera 30 of the present embodiment is equipped with the zoom lens 1of the present disclosure. Therefore, the camera 30 is capable ofobtaining images having high image quality.

The present disclosure has been described with reference to theembodiments and Examples thereof. However, the zoom lens of the presentdisclosure is not limited to the embodiments and Examples describedabove, and various modifications are possible. For example, the valuesof the radii of curvature of each lens, the distances among surfaces,the refractive indices, and the Abbe's numbers are not limited to thoseshown in the Examples above, and may be other values.

In addition, a non reflex digital camera was described as the embodimentof the imaging apparatus. However, the present disclosure is not limitedto this application, and may be applied to other imaging apparatuses,such as a video camera, digital cameras other than those of the nonreflex type, a cinematic camera, and a broadcast camera.

What is claimed is:
 1. A zoom lens consisting of, in order from theobject side to the image side: a first lens group having a positiverefractive power; a second lens group having a negative refractivepower; a third lens group having a positive refractive power; a fourthlens group having a positive refractive power; a fifth lens group havinga negative refractive power; and a sixth lens group having a positiverefractive power; the first lens group moving toward the object side,the distance between the first lens group and the second lens groupincreasing, the distance between the second lens group and the thirdlens group decreasing, the distance between the third lens group and thefourth lens group changing, the distance between the fourth lens groupand the fifth lens group changing, and the distance between the fifthlens group and the sixth lens group changing, when changingmagnification from the wide angle end to the telephoto end; the firstlens group consisting of, in order from the object side to the imageside, a negative 1A lens, a positive 1B lens, and a positive 1C lens;the second lens group having a 2R lens group having a negativerefractive power as a whole and consisting of a cemented lens formed bycementing a negative lens and a positive lens, which are provided inthis order from the object side to the image side, together, and anegative single lens; and the fifth lens group consisting of, in orderfrom the object side to the image side, a negative 5A lens, a negative5B lens, and a positive 5C lens.
 2. A zoom lens as defined in claim 1,in which Conditional Formula (1) below is satisfied:−0.3<f2/f1<−0.1  (1) wherein f2 is the paraxial focal length withrespect to the d line of the second lens group, and f1 is the paraxialfocal length with respect to the d line of the first lens group.
 3. Azoom lens as defined in claim 2, in which Conditional Formula (1-1)below is satisfied:−0.25<f2/f1<−0.15  (1-1).
 4. A zoom lens as defined in claim 1, in whichConditional Formula (2) below is satisfied:−0.9<f2/f3<−0.6  (2) wherein f2 is the paraxial focal length withrespect to the d line of the second lens group, and f3 is the paraxialfocal length with respect to the d line of the third lens group.
 5. Azoom lens as defined in claim 4, in which Conditional Formula (2-1)below is satisfied:−0.8<f2/f3<−0.7  (2-1).
 6. A zoom lens as defined in claim 1, wherein:the second lens group has a 2F lens group that includes a cemented lensformed by cementing a positive lens and a negative lens, provided inthis order from the object side to the image side, together, adjacent tothe 2R lens group at the object side thereof.
 7. A zoom lens as definedin claim 1, in which Conditional Formula (3) below is satisfied:0.8<f2/f2R<1.4  (3) wherein f2 is the paraxial focal length with respectto the d line of the second lens group, and f2R is the paraxial focallength with respect to the d line of the 2R lens group.
 8. A zoom lensas defied in claim 7, in which Conditional Formula (3-1) below issatisfied:1<f2/f2R<1.25  (3-1).
 9. A zoom lens as defined in claim 1, wherein: the2R lens group is moved in a direction perpendicular to the optical axisin order to correct for camera shake.
 10. A zoom lens as defined inclaim 1, wherein the fifth lens group moves toward the image side whenchanging focus from that on an object at infinity to that on an objectat a most proximal distance.
 11. A zoom lens as defined in claim 1, inwhich Conditional Formula (4) below is satisfied:−0.25<f5/f1<−0.05  (4) wherein f5 is the paraxial focal length withrespect to the d line of the fifth lens group, and f1 is the paraxialfocal length with respect to the d line of the first lens group.
 12. Azoom lens as defined in claim 11, in which Conditional Formula (4-1)below is satisfied:−0.2<f5/f1<−0.1  (4-1).
 13. A zoom lens as defined in claim 1, in whichConditional Formula (5) below is satisfied:0.8<f5A/f5<1.3  (5) wherein f5A is the paraxial focal length withrespect to the d line of the negative 5A lens, and f5 is the paraxialfocal length with respect to the d line of the fifth lens group.
 14. Azoom lens as defined in claim 13, in which Conditional Formula (5-1)below is satisfied:0.9<f5A/f5<1.2  (5-1).
 15. A zoom lens as defined in claim 1, in whichConditional Formula (6) below is satisfied:45<(vd5A+vd5B)/2<80  (6) wherein vd5A is the Abbe's number with respectto the d line of the negative 5A lens, and vd5B is the Abbe's numberwith respect to the d line of the negative 5B lens.
 16. A zoom lens asdefined in claim 15, in which Conditional Formula (6-1) below issatisfied:50<(vd5A+vd5B)/2<75  (6-1).
 17. A zoom lens as defined in claim 1,wherein: the third lens group has a 3A cemented lens, in which apositive lens and a negative lens provided in this order from the objectside to the image side are cemented together, and a 3B cemented lens, inwhich a positive lens and a negative lens provided in this order fromthe object side to the image side are cemented together.
 18. A zoom lensas defined in claim 1, further comprising: a stop positioned adjacent tothe third lens group at the image side thereof; and wherein: the stopmoves integrally with the third lens group when changing magnification.19. A zoom lens as defined in claim 1, wherein: the sixth lens groupconsists of a positive 6A lens.
 20. An imaging apparatus equipped withthe zoom lens as defined in claim 1.